Method for semi-statically adapting uplink multiple-input multiple-output transmission

ABSTRACT

A method, a wireless terminal device, and a base station are disclosed. A receiving unit  408  may receive from a base station an antenna precoding instruction for an uplink transmission. A processor  304  may execute a modification of the antenna precoding instruction according to a transmit antenna adapter into a customized precoding. A transmitting unit  406  may perform the uplink transmission according to the customized precoding.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 12/577,105, filed Oct. 9, 2009, the disclosure of which ishereby incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a method and system for performing anuplink transmission with a base station. The present invention furtherrelates to applying a customized precoding to a transmitting unit of awireless terminal device.

INTRODUCTION

The Third Generation Partnership Project (3GPP) is developing a LongTerm Evolution (LTE) standard using a physical layer based on globallyapplicable evolved universal terrestrial radio access (E-UTRA). Inrelease-8 specification of LTE, an LTE base station, referred to as anenhanced Node-B (eNB), may use an array of four antennas, or even morewith antenna virtualization, to broadcast a signal to a piece of userequipment (UE), such as a wireless terminal device.

Depending on different channel condition, eNB may instructs a UE on howto use its multiple antennas in the uplink transmission. For example inthe case of precoding, the UE may apply a different weighting and phaseoffset to the signal to be sent from each of the transmit antenna. Aprecoding operation may be represented mathematically by a vector ofcomplex-valued weightings applied onto the transmission signal of eachantenna. The eNB may dynamically instruct a precoding matrix index(PMI), selected from a pre-defined set of matrices known to the UE. Thepre-defined set of matrices is known as a codebook.

SUMMARY OF THE INVENTION

A method, a wireless terminal device, and a base station are disclosed.A receiving unit may receive from a base station an antenna precodinginstruction for an uplink transmission. A processor may execute amodification of the antenna precoding instruction according to atransmit antenna adapter into a customized precoding. A transmittingunit may perform the uplink transmission according to the customizedprecoding.

BRIEF DESCRIPTION OF THE DRAWINGS

Understanding that these drawings depict only typical embodiments of theinvention and are not therefore to be considered to be limiting of itsscope, the invention will be described and explained with additionalspecificity and detail through the use of the accompanying drawings inwhich:

FIG. 1 illustrates in a block diagram one embodiment of a communicationsystem.

FIG. 2 illustrates a possible configuration of a computing system to actas a base transceiver station.

FIG. 3 illustrates, in a block diagram, one embodiment of a mobilesystem or electronic device to create a radio connection.

FIG. 4 illustrates, in a block diagram, one embodiment of a transceiver.

FIG. 5 illustrates, in a block diagram, one embodiment of a controlmessage transmission.

FIG. 6 illustrates, in a block diagram, one embodiment of an adaptermessage transmission.

FIG. 7 illustrates, in a flowchart, one embodiment of a method forreceiving an uplink transmission.

FIG. 8 illustrates, in a flowchart, one embodiment of a method forperforming an uplink transmission with a base station created transmitantenna adapter.

FIG. 9 illustrates, in a block diagram, one embodiment of a feedbackmessage transmission.

FIG. 10 illustrates, in a block diagram, one embodiment of amodification/confirmation message transmission.

FIG. 11 illustrates, in a flowchart, one embodiment of a method forperforming an uplink transmission with a user equipment created transmitantenna adapter.

FIG. 12 illustrates, in a flowchart, one embodiment of a method formodifying an antenna precoding instruction with a transmit antennaadapter.

DETAILED DESCRIPTION OF THE INVENTION

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. Thefeatures and advantages of the invention may be realized and obtained bymeans of the instruments and combinations particularly pointed out inthe appended claims. These and other features of the present inventionwill become more fully apparent from the following description andappended claims, or may be learned by the practice of the invention asset forth herein.

Various embodiments of the invention are discussed in detail below.While specific implementations are discussed, it should be understoodthat this is done for illustration purposes only. A person skilled inthe relevant art will recognize that other components and configurationsmay be used without parting from the spirit and scope of the invention.

The present invention comprises a variety of embodiments, such as amethod, a mobile system, and a mobile network operator, and otherembodiments that relate to the basic concepts of the invention. Themobile system may be any manner of computer, mobile device, or wirelesscommunication device.

A method, a wireless terminal device, and a base station are disclosed.A receiving unit may receive from a base station an antenna precodinginstruction for an uplink transmission. A processor may execute amodification of the antenna precoding instruction according to atransmit antenna adapter into a customized precoding. A transmittingunit may perform the uplink transmission according to the customizedprecoding.

A wireless terminal device with multiple transmit (Tx) antennas, due todifferent form factor constraints, may have many potential antennaimplementations, including different antenna spacing, the use ofdual-polarized or linear-polarized antenna elements, and various degreesof antenna coupling. Different antenna implementations tailored fordifferent device form factors may often result in different levels oftransmit antenna correlation, and differing antenna efficiencies. Inaddition, various propagation scenarios in which the devices are used,such as the hand-grip posture for handheld devices and usage posture fornotebooks, may affect the antenna correlation and efficiency. Thetransmit antenna correlation may be learned at the base station when thechannel corresponding to each of the transmit antennas of a wirelessdevice may be estimate from an uplink sounding signal transmission.Alternatively, the wireless terminal device may estimate the transmitantenna correlation from estimating the receive antenna correlation,assuming the set of transmit antennas is a subset of the receiveantennas and the downlink to uplink reciprocity holds. Even if not, thewireless terminal device may extract some coarse characteristicsembedded in the receive antenna correlation. Depending on the observedchannel statistics, especially the long-term property caused by antennaimplementation, configuration, or usage posture, the uplinkmultiple-input multiple-output transmission may adapt to these channelstatistics.

One case where the configuration of antennas may be adapted is when theimplantation of a user equipment device may have antenna efficiencydifference, also called gain imbalance. To deal with gain imbalance, abase station may use only a subset of the terminal antennas for uplinktransmission, referred to as a reduced-dimension precoding. One way tosupport a reduced dimension precoding may be to define a “master”codebook that covers all the possibilities of dimension reduction. Sincethe activated antenna subset depends on the antenna configuration andusage posture, the master codebook may have to accommodate multiplepossibilities, and therefore include many reduced-dimension codebooksthat are essentially the same except that they apply to differentantenna subset groupings. However, defining the master codebook toinclude basically multiple replicas of the same reduced dimensioncodebook to cover all possibilities may not be efficient, since theamount of control signaling may grow with the size of the codebook.Generally, the optimal choice of subset may change relatively slowly.This may be due to the optimal choice of subsets being primarilyinfluenced by antenna gain imbalance. Antenna gain imbalance may beinfluenced, in turn, by such events as change in user hand grip, userposture, and antenna configuration, which occur infrequently relative tothe rate of signaling the choice of precoding matrix within thecodebook. While replicating a base codebook to address all permutationsof antenna indexing is possible, such replication may not be the mostefficient approach when re-indexing is needed fairly infrequently.

In another situation, the codebook may be defined with a particularantenna type and indexing in mind which does not match the actualimplementation. In this case, the base station may change the antennaindexing. Such a decision may be based on the uplink channel observed atthe base station based on the sounding signal transmitted from the userdevice. Precoding performance may be improved if the optimal antennaindexing is adjusted. The change in antenna indexing may be done once bya user equipment device autonomously or according to some criteriadefined by the base station. Once defined, the user equipment may usethe antenna indexing in all subsequent uplink transmissions, includingthe transmission of a sounding signal. In an alternative procedure, theuser equipment may sound from antennas with a first indexing which serveas a reference index, and then potentially be changed by the basestation based on the received sounding signal. In such cases the basestation may signal the new antenna indexing. The appropriate indexingmay change according to hand grip and user posture. Ideally, the basestation may optimally determine the appropriate indexing on asemi-static basis, according to the antenna implementation, usageposture, and the predefined codebook. The base station may convey suchantenna re-indexing to a user equipment device.

Similar to antenna indexing, the user equipment device may groupantennas based on a property to best match the predefined codebook. Forexample, antenna of the same or orthogonal polarization, or antennas ofclose spacing, may be grouped together so that precoding may betterexploit high antenna correlation for transmission directivity gain andlow antenna correlation for spatial multiplexing gain. Antenna groupingmay be achieved through re-indexing.

Overall, the antenna characteristics inherent to the implementation andsome long-term propagation behavior may affect the long-term behavior ofthe channel significantly. Semi-static notification of antenna indexing,or grouping, or subset selection may be beneficial.

FIG. 1 illustrates one embodiment of a communication system 100. Thecommunication system 100 may include a core mobile network 102 that maybe accessed by at least one mobile device 104, such as a wirelessterminal device, or user equipment (UE). The wireless terminals 104 maybe fixed or mobile. The wireless terminals 104 may also be referred toas subscriber units, mobiles, mobile stations, user, terminals,subscriber stations, user terminals, wireless communication devices,user devices, or by other terminology used in the art. Variouscommunication devices may exchange data or information through the coremobile network 102. The core mobile network 102 may be a WiMAX network,a universal terrestrial radio access network (UTRAN) cellular network,an evolved UTRAN (E-UTRAN) cellular network, or other type oftelecommunication network. A server or a series of servers controlled bya network operator, referred to herein as a network operator server 106,or a mobile network operator 106, may administer the network. Thenetwork operator server 106 may maintain a set of data to facilitateaccess of the core mobile network 102 by the wireless terminal device104. The mobile system 104 may access the network via a network basestation 108. A base unit 108 may also be referred to as an access point,access terminal, base, base station, Node-B, eNode-B, Home Node-B, HomeeNode-B, relay node, or by other terminology used in the art.

FIG. 2 illustrates a possible configuration of a computing system 200 toact as a network operator server 106 or a network base station 108. Thecomputing system 200 may include a controller/processor 210, a memory220, a database interface 230, a transceiver 240, input/output (I/O)device interface 250, and a network interface 260, connected through bus270. The network server 200 may implement any operating system. Clientand server software may be written in any programming language, such asC, C++, Java or Visual Basic, for example. The server software may runon an application framework, such as, for example, a Java® server or.NET® framework

The controller/processor 210 may be any programmed processor known toone of skill in the art. However, the disclosed method may also beimplemented on a general-purpose or a special purpose computer, aprogrammed microprocessor or microcontroller, peripheral integratedcircuit elements, an application-specific integrated circuit or otherintegrated circuits, hardware/electronic logic circuits, such as adiscrete element circuit, a programmable logic device, such as aprogrammable logic array, field programmable gate-array, or the like. Ingeneral, any device or devices capable of implementing the disclosedmethod as described herein may be used to implement the disclosed systemfunctions of this invention.

The memory 220 may include volatile and nonvolatile data storage,including one or more electrical, magnetic or optical memories such as arandom access memory (RAM), cache, hard drive, or other memory device.The memory may have a cache to speed access to specific data. The memory220 may also be connected to a compact disc-read only memory (CD-ROM),digital video disc-read only memory (DVD-ROM), DVD read write input,tape drive, or other removable memory device that allows media contentto be directly uploaded into the system.

Data may be stored in the memory or in a separate database. The databaseinterface 230 may be used by the controller/processor 210 to access thedatabase. The database may contain subscriber information for eachmobile system 104 that may access the mobile network 102. Further, thedatabase may maintain network performance data, such as networktopology, network geographic location and peer proximity, network loaddistribution, and other network data.

The transceiver 240 may create a connection with the mobile device 104.The transceiver 240 may be incorporated into a base station 200 or maybe a separate device.

The I/O device interface 250 may be connected to one or more inputdevices that may include a keyboard, mouse, pen-operated touch screen ormonitor, voice-recognition device, or any other device that acceptsinput. The I/O device interface 250 may also be connected to one or moreoutput devices, such as a monitor, printer, disk drive, speakers, or anyother device provided to output data. The I/O device interface 250 mayreceive a data task or connection criteria from a network administrator.

The network connection interface 260 may be connected to a communicationdevice, modem, network interface card, a transceiver, or any otherdevice capable of transmitting and receiving signals from the network.The network connection interface 260 may be used to connect a clientdevice to a network. The components of the network server 200 may beconnected via an electrical bus 270, for example, or linked wirelessly.

Client software and databases may be accessed by thecontroller/processor 210 from memory 220, and may include, for example,database applications, word processing applications, as well ascomponents that embody the disclosed functionality of the presentinvention. The network server 200 may implement any operating system.Client and server software may be written in any programming language.Although not required, the invention is described, at least in part, inthe general context of computer-executable instructions, such as programmodules, being executed by the electronic device, such as a generalpurpose computer. Generally, program modules include routine programs,objects, components, data structures, etc. that perform particular tasksor implement particular abstract data types. Moreover, those skilled inthe art will appreciate that other embodiments of the invention may bepracticed in network computing environments with many types of computersystem configurations, including personal computers, hand-held devices,multi-processor systems, microprocessor-based or programmable consumerelectronics, network PCs, minicomputers, mainframe computers, and thelike.

FIG. 3 illustrates one embodiment of a wireless terminal device 300,capable of acting as a mobile system or electronic device. For someembodiments of the present invention, the mobile device 300 may alsosupport one or more applications for performing various communicationswith a network. The mobile device 300 may be a handheld device, such as,a mobile phone, a laptop, or a personal digital assistant (PDA). Forsome embodiments of the present invention, the user device 300 may beWiFi® capable device, which may be used to access the network mobile fordata or by voice using VOIP.

The mobile device 300 may include a transceiver 302, which is capable ofsending and receiving data over the mobile network 102. The mobiledevice 300 may include a processor 304 that executes stored programs.The mobile device 300 may also include a volatile memory 306 and anon-volatile memory 308 to act as data storage for the processor 304.The mobile device 300 may include a user input interface 310 that maycomprise elements such as a keypad, display, touch screen, and the like.The mobile device 300 may also include a user output device that maycomprise a display screen and an audio interface 312 that may compriseelements such as a microphone, earphone, and speaker. The mobile device300 also may include a component interface 314 to which additionalelements may be attached, for example, a universal serial bus (USB)interface or a geographical positioning system (GPS). Finally, themobile device 300 may include a power supply 316.

FIG. 4 illustrates one embodiment of a transceiver 302. A terminalinterface 402 may send received signals to the UE device 104 and receivetransmissions from the UE device 104. A controller 404 may configure atransmitting unit 406 according to an antenna codebook received from thebase station 108 by a receiving unit 408. Alternately, the transceiver302 may forgo the controller 404 and have the configuration performed bythe processor 304 of the UE device 104.

The base station 108 may send the antenna precoding instruction to theUE device 104 in a control message transmission. FIG. 5 illustrates oneembodiment of a control message transmission 500. The control messagetransmission 500 may have a transmission format field 502 to indicatethe format of the subsequent transmissions. The control messagetransmission 500 may have a cyclical redundancy check (CRC) filed 504 toaid in determining if the message is correctly by the UE device 104. Thecontrol message transmission 500 may have power control information 506to aid the UE device 104 in setting its transmit power. The controlmessage transmission 500 may have an antenna codebook 508 describing oneor more antenna precoding instruction 510 to indicate to the UE device104 the precoding matrix to be used on a subsequent matrix to be used ona subsequent uplink transmission. The base station 108 may send thecontrol message transmission 500 on a recurring basis to the UE device104.

The antenna codebook may be customized to an individual UE device 104using a transmit antenna adapter. The base station 108 may send arepresentation of a transmit antenna adapter to the UE device 104 in anadapter message transmission. FIG. 6 illustrates one embodiment of anadapter message transmission 600. The adapter message transmission 600may have a CRC 602 to aid in the detection of errors in the messagereceived by the UE device 104. The adapter message transmission 600 mayhave a UE ID 604 for the UE device 104 and a message length field 606.The adapter message transmission 600 may have a transmit antenna adapterrepresentation 608 describing a transmit antenna adapter. The transmitantenna adapter may modify an antenna precoding instruction 510 toinstruct a transmitting unit 406 to configure a set of transmitantennas. The base station may also send the adapter messagetransmission 600 on a recurring basis to the UE device 104. The basestation may send the adapter message transmission 600 at a differentinterval from the control message transmission 500.

The antenna adapter may be represented in various forms, but moregenerically as a matrix “A” to be used in uplink transmission, possiblytogether with the precoding matrix V_(P×N), in the following equation:X _(M) _(T) _(×N) =A _(M) _(T) _(×P) *V _(P×N) *S _(N×1)where X_(M) _(T) _(×N) is the transmitted signal from all M_(T) antennasfor N streams or layers of data represented by S_(N×1) (i.e., rank-N),and V_(P×N) is the precoding matrix of dimension P rows, where the valueP is between N and M_(T). The precoding matrix V_(P×N) may be absent ifit is an identity matrix. In one embodiment, the transmit antennaadapter representation 608 may be a bit field, which indicates theantenna adapter to be applied. A bit field of with a value of “0”, forexample, may indicate for the UE device 104 to use the adapter describedby the matrix A_(M) _(T) _(×P) (0), while a bit field with a value of“1” may indicate for the UE device 104 to use the adapter described bythe matrix A_(M) _(T) _(×p) (1), A_(M) _(T) _(×P)(0) and A_(M) _(T)_(×P)(1) where represent two possible adapters in a set ofpossibilities. The transmit antenna adapter may modify the antennaprecoding instruction 510 according to multiple schemes indicated in theadapter representation, including antenna subset selection, antennaindex permutation, or antenna pattern virtualization. For example, whenthe transmit antenna adapter modifies the antenna precoding instruction510 by antenna subset selection, the matrix A_(M) _(T) _(×P) may be anantenna subset selection matrix. A subset selection matrix may be amatrix with entries with values of either “0” or “1”, have at most one“1” in each row. For example, if antenna 1 and 3 is selected fortransmission out of all 4 UE antennas, the matrix A_(M) _(T) _(×P) is aselection matrix and may be represented as:

$A_{M_{T} \times P} = {\begin{bmatrix}1 & 0 \\0 & 0 \\0 & 1 \\0 & 0\end{bmatrix}.}$

As described earlier, a UE device 104 may implicitly index the antennaswhen performing uplink sounding signal transmission. The base station108 may want to re-index the antennas based on the observed long-termstatistics so that a codebook may deliver better performance, as opposedto the original codebook without antenna re-indexing. The originalcodebook without re-indexing may be represented by an identity matrixA_(M) _(T) _(×P)=I_(4×4). The base station 108 may request the UE device104 to re-index its transmit antennas by sending an adapter messagetransmission 600 indicating the transmit antenna adapter may re-indexthe transmit antennas. The re-indexing may be represented by apermutation matrix A_(M) _(T) _(×P). A permutation matrix may be amatrix with exactly one entry in each column equal to “1” and theremaining entries equal to “0”. For example, the UE device 104 mayre-index the 4 antennas to [1,3,2,4] with the following permutationmatrix:

$A_{M_{T} \times P} = {\begin{bmatrix}1 & 0 & 0 & 0 \\0 & 0 & 1 & 0 \\0 & 1 & 0 & 0 \\0 & 0 & 0 & 1\end{bmatrix}.}$

The base station 108 may determine, on a semi-static basis, the bestantenna indexing based on the antenna correlation observed. Morespecifically, the base station 108 may decide which permutation givesthe best performances under the observed antenna correlation. Thedecision may be specific to an implementation based on, for example,criterion used in typical codebook design. The codebook design criterionmay include, for example, minimal codeword distance.

Not limited to antenna selection or indexing, another scheme formodifying the antenna precoding may employ the adapter matrix A_(M) _(T)_(×P) based on the user equipment transmit antenna correlation orcovariance matrix “R”. In a particular example, A_(M) _(T)_(×P)=R^(1/2), or the square root of “R”, may be used for adaptiveuplink precoding. Here “R” may be the correlation or covariance matrixof the vector of channels corresponding to the link between each of thetransmit antennas and a certain receive antenna, or the average ofseveral such covariance matrices, with each corresponding to one receiveantenna of the base unit. In general, “antenna pattern virtualization”may be referred to as the process of applying a unitary matrix totransform a set of physical antennas to a set of virtualized antennasvia weighting the set of physical antennas according to the unitarymatrix. The above covariance matrix based antenna adaption scheme may bereferred to as antenna pattern virtualization.

Regardless of which of the three methods of transmit antenna adaptionused: subset selection, antenna re-indexing, or covariance matrix-basedpattern virtualization, and thus the form of the adapter matrix A_(M)_(T) _(×P); the user equipment may combine the precoding matrix indexindicated in the precoding instruction, represented by V_(P×N), with theadapter matrix A_(M) _(T) _(×P) to determine the actual precodingmatrix. If more than one non-zero entry is present in any row of thecombined precoding matrix A_(M) _(T) _(×P)*V_(P×N), the emitted signalon the corresponding antenna may be the weighted superposition of two ormore waveforms.

Note that the three methods of transmit antenna adaptation mentioned:subset selection, antenna re-indexing, or covariance matrix-basedpattern virtualization, may be applied to a submatrix of the precodingmatrices. For example, with three layers or data streams, the precodingmatrix V_(P×N) may have three columns. A submatrix having only twocolumns, for example, may be adapted according to the adapter, insteadof having the whole matrix adapted. In other words, the adapter matrixmay apply to the submatrix of any precoding matrix indicated in theprecoding instruction.

FIG. 7 illustrates one embodiment 700 of a method for receiving anuplink transmission. The base station 108 may receive an uplinktransmission from the UE device 104 (Block 702). The base station 108may obtain an uplink channel correlation of the uplink transmission(Block 704). The base station 108 may determine a transmit antennaadapter based on the uplink channel correlation and a codebook (Block706). The decision may also be based on an uplink channel correlationobtained from the uplink transmission and the precoding indicated by theantenna precoding instruction. The transmit antenna adapter may be a setof modifications to the precoding operation in order to make the antennaprecoding instruction 510 better match the antenna configuration of theUE device 104 and the transmission characteristics of the uplinktransmission. The base station 108 may send the UE device 104 an antennaprecoding instruction 510 for an uplink transmission (Block 708). Thebase station 108 may send the antenna precoding instruction 510 on arecurring basis. The base station 108 may send a transmit antennaadapter representation to the UE device 102 (Block 710). The transmitantenna adapter representation may describe to the UE device 104 thetransmit antenna adapter. The base station 108 may send the transmitantenna adapter representation on a different interval than the antennaprecoding instruction 510.

FIG. 8 illustrates one embodiment of a method 800 for performing anuplink transmission with a base station created transmit antennaadapter. The UE device 104 may transmit from a set of antennas to allowthe base station 108 to estimate the uplink channel (Block 802). The UEdevice 104 may receive from the base station 108 a control messagetransmission 500 containing an antenna precoding instruction 510 for anuplink transmission (Block 804). The UE device 104 may receive from thebase station 108 a transmit antenna adapter representation (Block 806).The UE device 104 may receive both the antenna precoding instruction 510and the antenna adapter representation on a recurring basis. The UEdevice 104 may receive the antenna precoding instruction 510 on adifferent interval than the transmit antenna adapter representation. TheUE device 104 may execute a modification of the antenna precodinginstruction 510 into a customized precoding according to a transmitantenna adapter (Block 808). The UE device 104 may then perform theuplink transmission according to the customized precoding (Block 810).

Alternatively, a UE device 104 may adapt the transmit antennasautonomously based on measurement of the downlink channel and maycommunicate the information back to the base station 108. The downlinkmeasurement may capture the uplink channel in case of a time divisionduplexing system which may have channel reciprocity between uplink anddownlink. Even in frequency division duplexing, a UE device 104 maystill be able to extract a transmit antenna property to make a decisionon the preferred antenna adaptation.

The UE device 104 may determine the transmit antenna adapter based on adownlink transmission. The UE device 104 may then send a representationof a UE-preferred transmit antenna adapter to the base station 108 forconfirmation in a feedback message transmission. FIG. 9 illustrates oneembodiment of a feedback message transmission 900. The feedback messagetransmission 900 may have a CRC 902 to aid in the detection of errors inthe message received by the base station 108. The feedback messagetransmission 900 may have a message length field 904 for the basestation 108. The feedback message transmission 900 may have aUE-preferred transmit antenna adapter representation 906 describing apreferred or recommended transmit antenna adapter. The transmit antennaadapter may modify an antenna precoding instruction 510 to instruct atransmitting unit 406 to configure a set of transmit antennas. Thetransmit antenna adapter may modify the antenna precoding instruction510 as an antenna subset selection, an antenna index permutation, and anantenna pattern virtualization.

The base station 108 may review the UE-preferred transmit antennaadapter review representation 908 and make some modifications or justconfirm. The base station 108 may send these modifications orconfirmations to the UE device 104 in a modification/confirmationmessage transmission. FIG. 10 illustrates, in a block diagram, oneembodiment of a modification/confirmation message transmission. Themodification/confirmation message transmission 1000 may have a CRC 1002aid the UE device 104 in determining if an error was mad in thereception of the message. The modification/confirmation messagetransmission 1000 may have a UE ID 1004 for the UE device 104 and amessage length field 1006 for the base station 108. Themodification/confirmation message transmission 1000 may have a modifiedtransmit antenna adapter representation 1008 describing a modifiedtransmit antenna adapter or confirmation that the UE-preferred adapteris accepted as the transmit antenna adapter. The transmit antennaadapter may modify an antenna precoding instruction 510 to instruct atransmitting unit 406 to configure a set of transmit antennas. Thetransmit antenna adapter may modify the antenna precoding instruction510 as an antenna subset selection 1010, an antenna index permutation1012, and an antenna pattern virtualization 1014.

FIG. 11 illustrates one embodiment of a method 1100 for performing anuplink transmission with a UE determined transmit antenna adapter. TheUE device 104 may measure the downlink channel of the down linktransmission from the base station 108 (Block 1102). The UE device 104may determine a UE-preferred transmit antenna adapter based on thedownlink channel (Block 1104). The UE device 104 may send a transmitantenna adapter representation describing the UE-preferred transmitantenna adapter to the base station 108 (Block 1106). After the basestation 108 has reviewed the transmit antenna adapter representation,the UE device 104 may receive a modified antenna adapter representationor a confirmation from the base station (Block 1108). The UE device 104may receive from the base station 108 an antenna codebook containing anantenna precoding instruction 510 for an uplink transmission (Block1110). The UE device 104 may execute a modification of the antennaprecoding instruction 510 into a customized precoding according to atransmit antenna adapter (Block 1112). The UE device 104 may thenperform the uplink transmission according to the customized precoding(Block 1114).

FIG. 12 illustrates one embodiment of a method 1200 for modifying anantenna precoding instruction 510 with a transmit antenna adapter. Theantenna precoding instruction 510 may be formatted as an index into acodebook having a set of a precoding matrix. The UE device 104 may applya precoding entry on all or a subset of transmit antennas chosenaccording to the transmit antenna adapter (Block 1202). The UE device104 may execute a permutation of the precoding matrix according to anantenna permutation indicated by the transmit antenna adapter (Block1204). The permutation may be on the rows of the precoding matrix, orrows of a submatrix of the precoding matrix. The UE device 104 maymultiply the precoding matrix on the left by a unitary matrix indicatedby the transmit antenna adapter to transform a set of physical antennasto a set of virtualized antennas via weighting the set of physicalantennas according to the unitary matrix (Block 1206).

Embodiments within the scope of the present invention may also includecomputer-readable media for carrying or having computer-executableinstructions or data structures stored thereon. Such computer-readablemedia can be any available media that can be accessed by a generalpurpose or special purpose computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium which can be used to carryor store desired program code means in the form of computer-executableinstructions or data structures. When information is transferred orprovided over a network or another communications connection (eitherhardwired, wireless, or combination thereof) to a computer, the computerproperly views the connection as a computer-readable medium. Thus, anysuch connection is properly termed a computer-readable medium.Combinations of the above should also be included within the scope ofthe computer-readable media.

Embodiments may also be practiced in distributed computing environmentswhere tasks are performed by local and remote processing devices thatare linked (either by hardwired links, wireless links, or by acombination thereof) through a communications network.

Computer-executable instructions include, for example, instructions anddata which cause a general purpose computer, special purpose computer,or special purpose processing device to perform a certain function orgroup of functions. Computer-executable instructions also includeprogram modules that are executed by computers in stand-alone or networkenvironments. Generally, program modules include routines, programs,objects, components, and data structures, etc. that perform particulartasks or implement particular abstract data types. Computer-executableinstructions, associated data structures, and program modules representexamples of the program code means for executing steps of the methodsdisclosed herein. The particular sequence of such executableinstructions or associated data structures represents examples ofcorresponding acts for implementing the functions described in suchsteps.

Although the above description may contain specific details, they shouldnot be construed as limiting the claims in any way. Other configurationsof the described embodiments of the invention are part of the scope ofthis invention. For example, the principles of the invention may beapplied to each individual user where each user may individually deploysuch a system. This enables each user to utilize the benefits of theinvention even if any one of the large number of possible applicationsdo not need the functionality described herein. In other words, theremay be multiple instances of the electronic devices each processing thecontent in various possible ways. It does not necessarily need to be onesystem used by all end users. Accordingly, the appended claims and theirlegal equivalents should only define the invention, rather than anyspecific examples given.

We claim:
 1. A method for performing an uplink transmission with awireless terminal device, comprising: receiving, at the wirelessterminal, from a base station an antenna precoding instruction;receiving, at the wireless terminal, from the base station arepresentation of a transmit antenna adapter in an adapter transmissionmessage; modifying the antenna precoding instruction according to therepresentation of the transmit antenna adapter, wherein modifying theantenna precoding instruction comprises at least one of: (i) re-indexingthe transmit antenna, or (ii) covariance matrix-based patternvirtualization, wherein re-indexing the transmit antenna comprises usinga permutation matrix having one entry in each column equal to 1 andremaining entries equal to 0; and performing the uplink transmissionaccording to the modified precoding.
 2. The method of claim 1, whereinthe representation of a transmit antenna adapter is a bit fieldindicating the antenna adapter to be applied.
 3. The method of claim 1,wherein covariance matrix-based pattern virtualization comprises usingthe square root of a covariance matrix of a vector of channelscorresponding to a link between each of a plurality of transmit antennasand a certain receive antenna.
 4. The method of claim 1, furthercomprising: combining, by the user equipment, a precoding matrixindicated in the precoding instruction with an adapter matrix; and ifmore than one non-zero entry is present in any row of the combinedmatrix, emitting a signal on a corresponding antenna, wherein the signalis a weighted superposition of two or more waveforms.
 5. The method ofclaim 1, further comprising: receiving the transmit antenna adapterrepresentation from the base station at a different interval than theantenna precoding instruction.
 6. The method of claim 1, wherein themodifying the antenna precoding instruction multiplies a precodingmatrix representing the antenna precoding instruction by a unitarymatrix to transform a set of physical antennas to a set of virtualizedantennas via weighting the set of physical antennas according to theunitary matrix.
 7. The method of claim 1, wherein re-indexing transmitantenna is based on observed long term statistics of transmissionperformance.
 8. The method of claim 1, wherein re-indexing transmitantenna is based on an observed antenna correlation.
 9. The method ofclaim 1, wherein re-indexing transmit antenna is based on a criterion ofminimal codeword distance.
 10. A wireless terminal device for performingan uplink transmission, comprising: a receiving unit adapted to receivefrom a base station an antenna precoding instruction; one or moreprocessors configured to: receive from the base station a representationof a transmit antenna adapter in an adapter transmission message; modifythe antenna precoding instruction according to the representation of thetransmit antenna adapter, wherein modifying the antenna precodinginstruction comprises at least one of: (i) re-indexing the transmitantenna, or (ii) covariance matrix-based pattern virtualization, whereinre-indexing the transmit antenna comprises using a permutation matrixhaving one entry in each column equal to 1 and remaining entries equalto 0; and a transmitting unit adapted to perform uplink transmissionaccording to the modified precoding.
 11. The wireless terminal device ofclaim 10, wherein the transmitting unit sends a transmit antenna adapterrepresentation to the base station.
 12. The wireless terminal device ofclaim 10, wherein the receiving unit receives a transmit antenna adapterrepresentation from the base station.
 13. The wireless terminal deviceof claim 12, wherein the transmit antenna adapter representationrepresents a modified antenna adapter.
 14. The wireless terminal deviceof claim 12, wherein the receiving unit receives the transmit antennaadapter representation from the base station at a different intervalthan the antenna precoding instruction.
 15. The wireless terminal deviceof claim 10, wherein the transmit antenna adapter configures a set oftransmit antennas according to at least one of antenna index permutationor antenna pattern virtualization.
 16. A non-transitorycomputer-readable medium storing a set of instructions executable by aprocessor for performing a method, comprising: receiving, at thewireless terminal, from a base station an antenna precoding instruction;receiving, at the wireless terminal, from the base station arepresentation of a transmit antenna adapter in an adapter transmissionmessage; modifying the antenna precoding instruction according to therepresentation of the transmit antenna adapter, wherein modifying theantenna precoding instruction comprises at least one of: (i) re-indexingthe transmit antenna; or (ii) covariance matrix-based patternvirtualization wherein re-indexing the transmit antenna comprises usinga permutation matrix having one entry in each column equal to 1 andremaining entries equal to 0; and performing the uplink transmissionaccording to the modified precoding.
 17. The medium of claim 16, whereincovariance matrix-based pattern virtualization comprises using thesquare root of a covariance matrix of a vector of channels correspondingto a link between each of a plurality of transmit antennas and a certainreceive antenna.
 18. The medium of claim 16, further comprising:combining, by the user equipment, a precoding matrix indicated in theprecoding instruction with an adapter matrix; and if more than onenon-zero entry is present in any row of the combined matrix, emitting asignal on a corresponding antenna, wherein the signal is a weightedsuperposition of two or more waveforms.